How do ferrite materials absorb radar-frequency electromagnetic radiation?

Ferrite materials absorb radar-frequency electromagnetic radiation through a process involving the rotation of magnetic moments within the material's crystal structure.1

In small crystallites of ferrites, the incident radiation causes the magnetic moment to rotate at the frequency of the light (or radar wave). Because the absorption frequency is dependent on the specific shape and size of the crystal grain, a polycrystalline material containing a variety of grain sizes and shapes can effectively absorb energy across a broad range of radar frequencies.1

This property is particularly significant for stealth technology. While metallic materials typically reflect radar signals, allowing aircraft to be located, ferrite-based coatings—often referred to as "snooper paint"—absorb these signals instead. This absorption prevents the reflection of radar waves, thereby rendering the aircraft difficult to detect.12